So I had a totally out of the blue thing happened on the way to the gym tonight. Driving about 30 mph on a city road. And all of a sudden hear this clicking noise from out of nowhere. I used to have a cooling fan that would knock and it sounded a little like that. Pulled into a parking lot about a block down and let the engine idle while I examined it. After checking under the hood under the vehicle and everything I determined it was coming from underneath the engine by the transmission case. After turning the engine off, the clicking continued. Half expecting it to just wind down I gave it a second. After 20 to 30 seconds it was still clicking so I climb back under the car. Definitely coming from the transmission. Possibly the starter, Which is a little bit up on the side. But as I moved around, really sounded like the transmission. trying to get the noise to stop, I tried to start my Cherokee and nothing, But still clicking. Then I turned the key off and still clicking. Toggled the key on and off several times and finally the clicking stopped.
Now when I go to try to start the vehicle I get a couple clicks out of the starter and then a slow hiss, almost like something depressurizing, But no effort to even try and turn over. Now it’s the same every time I try to start it. A couple clicks and then a long slow hiss. It definitely sounds like a starter issue to me, except for the fact I am almost totally positive it’s coming from the transmission. Is it possible for a transmission to click like that while running, or when the engine is shut off? Also, I have never heard of a starter just randomly click while driving. Any thoughts...?

 

You asked for thoughts. Take them with a grain of salt right now, because I truly do not think I know what happened or is happening with it. There are things not making sense for me in my head. I am interested in it though, and would like to try and help if I could.. Even if just to get things started on your thread. Hopefully, eventually started with your Jeep.

My thoughts said to me there may have been one of the different relays or any of the solenoids or something like these things to make that clicking sound you heard when it first started. The fact that it continued to make the noise when the mechanicals were no longer operating any at all after you shut the Jeep down.. this makes me believe it may probably be related to something that is wrong electrically, and is caused a relay or solenoids to have only just enough power making them go on/off to produce the noises you heard.

This same reasoning goes along with having a starter now to only just make clicking noises when you try starting the Jeep. It makes me think it is not the starter itself being bad but, rather it could be there is inadequate power making it to the starter for some reason.

My first inclination is to say it may be either the actual power supply wire connected to the starter itself, the starter ground connection, or the main primary battery ground wire and/or connection. I kind of want to say of these choices most likely it is the main battery ground, since this would have a greater overall effect on the rest of the Jeep to make the clicking noises like it was doing. It does not exactly make sense to me yet how it would be able to continue and do this like that with having the power shutt off though?

I think to pull off the starter and have it inspected for proper operation and clean its terminals. Disconnect the other ends away from the starter of its feeder wiring and clean these areas up real good. Disconnect the main battery and engine grounds to clean all of those really well. I have heard a bad ground here can cause a hissing sound. I do not understand why or how it would be able to do that making a hiss sound like that though? I would definitely disconnect both of the battery cables and clean the posts and cable terminals, and make sure to verify having a good battery voltage static and while loaded under cranking conditions.

I would also take a large socket or a wrench and manually hand crank to turn the engine over myself before attempting any more restarts. To make sure it freely rotates and for this not to be the reason. It does not sound like it is to me, since it was running and you did the shutdown yourself with the key right before having the no-start condition. I would want to be 100% certain of this to not cause any damage just in case though, because these things can happen and if it were.. it has to begin at some point in time wether it be from the engine shuting itself down vs you having turned it off with the key. If it was becoming locked up just prior, the inertia of it being on and running could have kept it rotating. However, maybe it does not turn freely enough for the crank motor to be able and spin it up for initial start-up?

I did have thoughts maybe the hissing noise could be from the crank ventilation breather system? I am fairly certain our 4.0 Jeeps have the CCV and not a PCV set-up? Not sure how much of a difference it would make between the two for this if there were too much crankcase pressure building up? This does not exactly make sense to me but, it is a thought. I just do not see how the CCV could produce any hissing noises anymore now, since the starter does not engage to turn over the engine? I would still check it by standing near to it and listening while having a helper crank the engine for some reason or another? And I would place my finger over the inlets and outlets of the CCV, to feel wether or not there was air being sucked in and blown out of it while cranking when the opportunity became available if it begins cranking and still is not starting.

During starting attempts, I would want to listen very closely to everything possible in order try and to somehow determine exactly where the hiss noise is originating. I am not sure if a mechanics stethoscope would be beneficial for you? It would definitely probably require a helper to attempt a start for you to be ready and listening for it.
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I think the solenoid is shorted. Pull the starter and bench test it.

 

At this point the battery could be low as well.

At any rate, I wouldn't be doing anything while the starter is in the vehicle as you might end up smoking something.

 

And I'd be REAL careful doing this, as I think what you've got there now is essentially an arc welder.

 

A coincidence?

If the starter isn't fried by now check the ignition switch:



(from Cruiser54 archives)

OST, might be a good idea to confirm that the ignition switch is intact regardless.

 

Battery voltage.. Starter bench-test.. Wires and connections of the starter and battery.. Main engine compartment grounds.. Ignition switch and circuitry.. I think in this order. Also, consider rotating the crank with a wrench by hand to make sure it is not locked-up.

All of the critical relays too; oHm them out, and swap out the critical ones with the A/C and windshield wiper relays.